BACKGROUND

Nippon Hoso Kyokai (NHK) is Japan's sole public broadcaster, established in
1925. It is financially and operationally independent of the government and
corporate influence. It is supported by monthly receiver fees of ¥1,395 for
terrestrial broadcasts and an additional ¥945 for satellite broadcasts. These
receiving fees account for 97.3% of operating revenues. There are more than
eight million satellite receivers; two 24-hour satellite channels are being
broadcast by NHK. It began direct broadcasting satellite (DBS) service in July
1987; since then it has been growing steadily, and is expected to grow as a
major multimedia service for the next century. BSAT-1a (provided by Hughes
International) was launched in April 1997 to support growth of DBS.

NHK has two research institutes that provide both hardware and software.
Broadcast engineering is carried out by the NHK Science & Technical
Research Laboratories, which the WTEC team visited, while program development
is undertaken at the NHK Broadcasting Culture Research Institute. The NHK
Science and Technical Research Laboratories were established in 1930, just five
years after the start of radio broadcasting in Japan. The laboratories started
out with a staff of 16 who researched such areas as the acoustic design of
studios and the development of a domestic radio. The lab now has a staff of
some 315 people. It is now working to put new broadcast media into practical
use, and to improve equipment and systems for conventional broadcasting.
Vigorous research is also being conducted on broadcast systems of the future.
As Japan's sole integrated research institute for broadcast technology, the lab
has been key to NHK's progress. It carries out its mission for future systems
in three main areas:

new broadcasting services

improvement of conventional broadcast services

basic technology to support future broadcasting systems

TECHNOLOGY DEVELOPMENT ACTIVITIES

The NHK Science and Technical Research Laboratories is working on the
state-of-the-art broadcasting technologies presented below.

New Broadcasting Services

Following the success of DBS, the lab is engaged in the development of
digital broadcasting systems, such as ISDB (integrated services digital
broadcasting). Broadcast equipment, transmission systems and home receivers for
new broadcast media services are also main subjects. See the list below.

Hi-Vision (HDTV):

40-inch plasma display (PDP)

super HARP handheld camera

tri- CCD "Hi-Vision" camera

multimedia services on MUSE

½" "Hi-Vision" digital VTR

Satellite Broadcasting:

2.6/12/21 GHz-band satellite broadcasting system

onboard dish-antenna (shaped-beam antenna)

high power TWT (12 GHz and 22 GHz)

compact DBS mobile receiver

Digital Broadcasting:

ISDB (integrated services digital broadcasting)

satellite, terrestrial and cable digital broadcasting

bit-rate reduction coding

multimedia in broadcasting

Improvement of Conventional Broadcast Services

Studies on areas ranging from program production technology to reception
technology are conducted in order to improve such conventional broadcasting
services as FM radio and terrestrial TV broadcasting. The list of topics is
shown below.

desk-top program production (DTPP)

speech-speed conversion system

digital SNG

digital FPU

wide wavelength information color TV camera

intelligent robot camera

Basic Technology to Support Future Broadcasting Systems

Broadcast media will serve increasingly as the dominant source of
information in the future. The development of more advanced and varied forms of
broadcasting requires basic research into human sight and hearing, as well as
solid-state devices and materials. NHK is researching three dimensional
television systems (3D-TV) in addition to artificial intelligence (AI)
technology, ultrahigh-density recording, and optoelectronics devices. The list
is below:

ultrahigh-density digital recording

3-D "Hi-Vision" without special glasses

super 3-D sound

digital broadcast LSI

machine translation

liquid-crystal spatial light modulator

EL display

EQUIPMENT AND FACILITIES

Detailed information was presented on several key technology development
activities related to satellite communications. These activities are discussed
below.

DBS and Future Broadcast Services

Services currently use 12 GHz for both FSS and BSS. NHK broadcasts 2
programs, NTSC and HDTV (MUSE, 17 hours per day), and has about 10 million
satellite subscribers out of a total of 35 million overall subscribers. There
are 5 commercial TV broadcast networks in Japan. Digital TV broadcast is used
in the DVB-S transmission system (29 Mbps per transponder, 4 to 6 channels of
TV broadcast per carrier). PerfecTV started in 1996 and has 300,000 subscribers
using JCSat. NHK has BS-3 (NEC built) and BSAT-1 (Hughes built, launched in
April 97). BSAT-1 can transmit four 27 MHz channels out of 8 channels
allocated. NHK expects to start digital TV Service around 2000. The 8 channels
would consist of 4 analog and 4 digital channels.

NHK has a vision of what is needed for a future digital TV broadcast system.
It is developing ISDB for BSS- band (2 channels of HDTV in one transponder). As
the HDTV display is still costly (¥300,000 now, ¥150,000 next year for a 32"
display), a converter box for about ¥20,000 is seen as a way to go from analog
HDTV to digital. There is a lab prototype, which uses TC8PSK, QPSK and BPSK
with 40 Mbps rate per transponder in 27 MHz of bandwidth. The essential
information is QPSK at 1.2 Mbps (it gives a smaller picture when rain faded)
with high quality information at around 20 Mbps. Control information is BPSK. A
single unit switches between the three. This way the availability is 99.8% with
10 dB rain fade.

Satellite Broadcasting Technologies

The frequency of 21.4 to 22 GHz is allocated here for TV broadcasting. In
Tokyo, during the worst month there is 99% availability with 10 dB margin at 22
GHz while only 2 dB margin is needed for 12 GHz. Rain mitigation needs two
mechanisms, satellite power control and hierarchical transmission. The
carrier-to-noise-ratio (C/N) is 7.1 dB for QPSK rate ½, 10 dB for QPSK rate ¾
and 12.7 dB for TC8PSK rate 2/3. NHK designs for 7 dB power control range in
satellite EIRP with two parallel TWTs. The system has 10 dB fade margin in
which a 3 dB margin is inherent. The TWT is a NEC helix with variable power
from 40 to 230 W at 22 GHz with 53% efficiency. Conduction cooling is used. Its
mass is 1.1 kg. EPC for the tubes runs around 12 kV. The antenna for
operational use must have 6 beams, 2.8 m reflector and 47 dBi.

Dr. Shogen presented a satellite newsgathering setup. A flat antenna for 14
GHz with 16 SSPAs is mounted on a gimbaled pedestal that tracks low rate
motion. Fast steering is electronic via 16 8x8 element phased arrays, with 16
phase shifters (the 8x8 element subarrays are fixed). A 17th array is for
grating lobe suppression. The SSPA has 5 W, total 80 W, and 30 W losses. The 3
center subarrays can receive 12 GHz and feed a beacon receiver to point the
beam. Experiments at sea worked well. NEC is building this for the commercial
market. At 14.5 GHz it has 513 dBW EIRP. Overall beam steering is plus or minus
2 degrees electrical, more mechanical and with overall 0.05 degrees pointing
accuracy.

A lab tour of facilities included antenna models, during which TWTs (Toshiba
and NEC) were shown. A prototype digital HDTV system was demonstrated through a
rainfade. The team also saw a true multimedia HDTV setup. Work to define user
desires is continuing. The idea is that TV broadcast downloads lots of
information into the local server. Information is immediately accessible and
automatically updated. Internet and other services can be accessed
simultaneously with TV pictures (smaller than full screen). For local storage
of program material, a mouseclick on the TV schedule will record.

CONCLUSIONS

NHK plays a central role on broadcasting in Japan. Its funding is assured
through monthly fees on every receiving household. There is no corresponding
entity in the United States. NHK provides a unified, stable, long-term outlook
for broadcast satellite development. NHK has a technology development program
that has provided progression from conventional BSS-TV at Ku-band, to HDTV
broadcast at Ku-band, and continuing through to possible DBS TV at 21 GHz. It
is engaged in the development of multimedia services by merging TV and PC
technologies which will have significant impact on the emerging information
infrastructure in the 21st century.